Recommendations requested for (laser) collimators

[Peterfludde]

Dear fellow Stargazers

Since two days ago I am the happy owner of a Stellalyra Dobsonian telescope, having caused a sensation at FLO HQ by collecting it myself. The team there could not have been more helpful, the manager - I think - somehow loading the very large box into our rather small car. Thank you sir.

I wanted to ask about collimators. Having researched for half a year and knowing I'd need to sort this out, I totally forgot when it came to the purchase.

Is there a make and/or model of collimator which is generally preferred, especially for beginners?

I'd be most grateful for any words of wisdom from old hands.

Best regards

Peter

 

 

[Mr Spock]

This is like the one I have:
https://www.amazon.co.uk/Svbony-Collimator-Telescope-Reflector-Collimation/dp/B013SMDQSY?ref_=ast_sto_dp

Works just fine. I collimate my 12" StellaLyra before each session. It's spot on with a star test.

I should add a lot of people recommend a Cheshire. I have the premium one and it's hard to use. You can't really see anything in the dark and it's awkward to adjust the collimation bolts. With a laser you can view it from the bottom of the telescope tube where the collimation bolts are - especially useful with larger scopes - I just don't have five foot arms 

 

[RT65CB-SWL]

I have and use these two...

• the Baader... https://www.firstlightoptics.com/other-collimation-tools/baader-laser-collimator.html
• and the HoTech SCA... https://www.firstlightoptics.com/hotech-collimation-tools/hotech-sca-laser-collimator-with-cross-hair.html

Laser collimators do or may need collimating too! - there a few video tutorials on YouTube on how to go about it if you are uncertain how to do it.

[Peterfludde]

Thank you for those most helpful replies

[dark knight]

+1 for the Hotech SCA, very easy to use even in the dark

[Guest]

Just remember that some of the lasers themselves will need to be colliniated before you ever get started.  Its not a hard process just time consuming and requires a bit of patience.  There are tons of videos online that woll show you how to do this.  

[bosun21]

Another thumbs up for the HoTech laser collimator. Like @Mr Spock I check my collimation on my Dobsonian before each session. Since upgrading the springs on my mirror cell it seldom needs to be tweaked. When it does it’s simplicity itself.

[Spile]

I would recommend a Cheshire eyepiece and sight tube combination tool (the Celestron and StellaLyra perform similarly) for alignment of your secondary and a cap for your primary. As per https://astro.catshill.com/collimation-guide/

[Giles_B]

+1 for the Baader from me (mine has held collimation well even after a drop to the floor) however I have two caveats:

1) any 1.25" collimating device in a 2" focuser will suffer from the imprecise alignment of the 2"->1.25" reducer. I found my collimation got a lot more precise with a Howie Glatter Parallizer https://www.firstlightoptics.com/adapters/howie-glatter-t-adapter-parallizer.html - but given these now cost almost £90, you may want to get a collimator with 2" capability in the first place.

2) I'd recommend at least having a collimating cap, and more usefully a Cheshire as backup. That way you can routinely check the laser has led to spot on collimation, check the secondary is correctly positioned and so forth. Often when I've asked for advice on forums about this or that issue, the first advice is to check collimation - having two (or more!) tools gives me greater confidence that the collimation is okay.

[wookie1965]

Some laser collimators need to be collimated themselves I have always used a Cheshire/sight tube. to make sure it is straight I use a self centering 2"-1.25" adapter no thumbscrews to pull it to one side.

Much easier to change eyepieces as well especially in winter when your fingers are cold and fiddling with the thumbscrews.

https://www.rothervalleyoptics.co.uk/ovl-twist-lock-adaptor-2-125.html

[Louis D]

I use a 1990s AstroSystems dual 1.25"/2" laser collimator.  The new one is 2"-only, but it does come with the Barlow attachment that mine did not.  I only use mine in 2" mode due to 2"-1.25" adapter uncertainty.

I mostly use it for secondary mirror alignment to the center of the primary.  I use a sight tube to center the secondary under the focuser and a Rigel Aline to do final alignment of the primary.  On my truss Dob, I do use the laser to align the return beam with the outgoing beam on the face of the secondary while crouching at the rear of the scope since I don't have 6' long arms to adjust the primary from the focuser.  I figure all the optical axes should then be aligned well enough at that point.  I do peep through the Aline as a double-check, though.

[woldsman]

20 hours ago, Spile said:

I would recommend a Cheshire eyepiece and sight tube combination tool (the Celestron and StellaLyra perform similarly) for alignment of your secondary and a cap for your primary. As per https://astro.catshill.com/collimation-guide/

+1 for the Cheshire 

[Peterfludde]

22 hours ago, Spile said:

I would recommend a Cheshire eyepiece and sight tube combination tool (the Celestron and StellaLyra perform similarly) for alignment of your secondary and a cap for your primary. As per https://astro.catshill.com/collimation-guide/

Thank you again for all the replies. Lots to think about. I think as a beginner I might go for the Cheshire option at first, if only because it seems reassuringly low-tech. Thank you Spile for that advice, and the link.

Best regards

Peter

 

 

[bomberbaz]

A concenter is a great tool.  I also have the Ocal electronic collimator.

Ocal Electronic Collimator | First Light Optics     

TS Concenter 1.25" Adjustment Eyepiece for Newtonian Telescopes | First Light Optics

I recently sold my hotech laser as it was deemed surplus to requirements. 

The Ocal is used when I am at home, gets it spot on, and I mean spot on.  The concenter out in the field when the scope is fully set up although it rarely needs more than a minor tweak.

Problem being both the above need light but given my experience with my scope, I am happy to keep what I have.

If I could only have one of anything, I think a concenter offers the best value / guaranteed accuracy.

[Mr Spock]

I used a Concentre for collimating my secondary, and a Cheshire for making sure my laser was aligned properly. This you need to do in daylight.

I'd like someone to demonstrate how you use a Cheshire, in the dark, from the bottom of 12" Newt...  

 

 

[Ratlet]

37 minutes ago, Mr Spock said:

I used a Concentre for collimating my secondary, and a Cheshire for making sure my laser was aligned properly. This you need to do in daylight.

I'd like someone to demonstrate how you use a Cheshire, in the dark, from the bottom of 12" Newt...  

 

 

How do you use a Cheshire to align a laster collimator?

[bomberbaz]

On 24/09/2022 at 13:13, Mr Spock said:

This is like the one I have:
https://www.amazon.co.uk/Svbony-Collimator-Telescope-Reflector-Collimation/dp/B013SMDQSY?ref_=ast_sto_dp

Works just fine. I collimate my 12" StellaLyra before each session. It's spot on with a star test.

I should add a lot of people recommend a Cheshire. I have the premium one and it's hard to use. You can't really see anything in the dark and it's awkward to adjust the collimation bolts. With a laser you can view it from the bottom of the telescope tube where the collimation bolts are - especially useful with larger scopes - I just don't have five foot arms 

 

Seems to be a lot of rather disparaging reviews on there Michael, although it is apparently collimatable. 

[Mr Spock]

16 minutes ago, Ratlet said:

How do you use a Cheshire to align a laster collimator?

Align your optics using the Cheshire, then align the laser to the optics. Mine didn't need adjusting. You can also align the laser by putting it in a fixed tube pointed at a spot some distance away. Rotate the laser collimator in the tube and see if the laser stays on the spot or rotates.

Make sure you buy a laser collimator which can be collimated in necessary - I see some can't be adjusted.

[CraigT82]

58 minutes ago, Mr Spock said:

I'd like someone to demonstrate how you use a Cheshire, in the dark, from the bottom of 12" Newt... 

It’s actually quite easy, but only if you swap your donut centre spot for a triangle one, and apply the triangle so that each point is pointing at a collimation bolt. That way just by looking through the Cheshire you can see which bolt to turn and which way to turn it. Granted there is still a little bit of back and forth between eyepiece and mirror end to get perfectly collimated so not quite what you asked, but much easier than turning the bolts randomly and seeing what happens.
 

 

[Spile]

I don’t align my mirrors in the dark. In fact my secondary mirror only need a tweak once in a while. The primary rarely even if I have had to transport it in the car.

[MarcuSmythe]

I apply 1 layer of tape around the cheap laser collimator. They can be sloppy otherwise.

[lvan]

A collimation cap may be all you need. It's about a fiver and a good choice for a beginner.

[wookie1965]

15 hours ago, Mr Spock said:

I used a Concentre for collimating my secondary, and a Cheshire for making sure my laser was aligned properly. This you need to do in daylight.

I'd like someone to demonstrate how you use a Cheshire, in the dark, from the bottom of 12" Newt...  

 

 

Use a Barlow with the laser then align the rings centrally bobs your uncle. 

Edited September 27, 2022 by wookie1965

[Buzz Parsec]

To keep a collimator collimated, I use a lego jig to rotate the laser and make sure it stays on spot; not create a little circle on a wall a few feet away.  I saw this on an American forum, so can't take any credit, but it's worth sharing.  2 mins to knock up if you have a small, lego or Minecraft minded child!

[SthBohemia]

On 26/09/2022 at 15:19, wookie1965 said:

laser collimators need to be collimated themselves

Mr @wookie1965 make that virtually ALL of them need collimating which is no great trouble, just dig out the silicon rubber guarding the collimation screws and re collimate. Says a lot for quality control.....